Facial Skeletal Augmentation with Porous Polyethylene Implants for Improved Aesthetics in the Setting of Congenital and Traumatic Facial Asymmetry

Introduction

The benefits of using high-density polyethylene implants (Medpor; Stryker, Kalamazoo, MI) in facial skeletal contouring have been well documented over the last two decades including low rates of implant infection and high patient satisfaction.^1,2 Implants can be obtained in standard sizes/shapes or customized with computer aided design and manufacturing (CAD/CAM) technology for patient-specific fit. Unfortunately, there are limited outcome reports in the setting of trauma and congenital deformity correction.^1,2 Therefore, we present our consecutive cohort experience with standard and customized prefabricated Medpor implants in complex craniomaxillofacial reconstruction.

Methods

All facial skeletal asymmetry of either congenital/traumatic etiologies reconstructed with standard or customized Medpor implants between 2011-2014 were included in this single surgeon retrospective cohort study.  Patient demographics, implant design methodology, complications, and follow up were documented. 

Surgical pearls:  In the most challenging circumstances, enhanced symmetry can be achieved using computed tomography and CAD/CAM technology to produce customized Medpor implants. Although the implants had adequate fit, all required intraoperative high-speed burring to smooth opposing bony/implant surfaces not only to refine contours, but also to eliminate gap/step-off deformity.  Depending on location of implant placement, incisions were camouflaged in the:  superior sulcus, retroseptal transconjuctival region, and bicoronal plane. Meticulous hemostasis and aseptic technique, along with subperiosteal dissection and titanium screw fixation, are essential to obtaining predictable outcomes. Further refinement includes draping soft tissue over the implant and noting areas of over-projection. In addition, one must always identify, preserve, and avoid compression of nearby sensory nerves.

Results

A cohort of 7 patients (2 female, 5 male) with facial asymmetry received a total of 10 Medpor implants (3 standard, 4 customized). The mean age was 35 ±15 years (range 21-57 years), with 3 congenital deformities (hemifacial microsomia, neurofibromatosis type 1, and Parry-Romberg Syndrome) and 4 post-traumatic asymmetries. Figure 1 shows the post-operative result at 4 months using a customized mandibular implant (arrow). Medpor implants were used to augment the orbit (n=5), mandible (n=2), piriform rim (=1), temporal region (n=1), and frontal bandeau (n=1).  Mean follow up time was 10 ±8 weeks (range 1-24). One patient experienced minor persistent concavity overlying the temporal implant, but did not desire revision. One patient developed surgical site cellulitis requiring intraoperative implant inspection, confirming localized epidermal involvement. No complications related to seromas, hematomas, or implant displacement- infection-removal have occurred to date.  All patients reported satisfaction with improved facial symmetry.

Conclusion

This small cohort demonstrates that Medpor implants can be used successfully and safely to aesthetically reconstruct congenital or traumatic craniomaxillofacial asymmetry.  Keys to success include careful preoperative planning with CAD/CAM technology and intraoperative modification with high speed burring to ensure optimal contour match. Further follow up is needed to determine long-term outcomes. 

Figure 1:

References

ADDIN RW.BIB1. Yaremchuk MJ. Facial skeletal reconstruction using porous polyethylene implants. Plast Reconstr Surg. 2003;111(6):1818-1827. 10.1097/01.PRS.0000056866.80665.7A [doi].

2. Frodel JL, Lee S. The use of high-density polyethylene implants in facial deformities. Arch Otolaryngol Head Neck Surg. 1998;124(11):1219-1223.